A “usage credit” is a flat dollar amount you only get if your billed usage clears a threshold in that cycle — and you lose all of it one kWh below. It’s a cliff, not a slope.
Real example — Reliant Power Savings 2,000 kWh 12. Its $150.00 credit lands only at 2,000 kWh. At 1,999 kWh you pay 21.5¢/kWh; add one more kWh to hit 2,000 kWh and it drops to 13.9¢. The curve below dives vertically at the threshold — that cliff is the whole product.
Interactive chart — open this example in the tool →
If your usage sits below the threshold most months, this plan is priced for someone else. The annual ranking above makes that concrete.